水圧破砕地殻応力計測時の破砕正に及ぼす水の浸透の影響と破砕圧の評価法

概要

論文の詳細を見る
A new method is proposed for the estimation of the so-called breakdown pressure in the hydraulic fracturing tectonic stress measurements. The stress field around the well bore was analyzed taking into account the influence of the fluid penetration into the porous rock due to the pressurization of the well bore. By the use of the stress field, the breakdown pressure, i. e., the well bore pressure required to induce cracks on the well bore was estimated based on a newly constructed fracture criterion. The criterion determines the breakdown pressure as a pressure value at which the maximum tensile effective stress at a characteristic depth beyond the well bore surface, reaches the tensile strength of the rock. To verify the new method, laboratory hydraulic fracturing experiments were conducted on cubical rock specimens under uniaxial compression. Results show that the breakdown pressures predicted by the classical method are erroneously lower than the experimental data when the uniaxial compressive stress is large. On the other hand, the breakdown pressures predicted by the present method perfectly agree with the experimental data independent of the magnitude of the uniaxial compressive stress.
一般社団法人日本機械学会の論文
1990-06-25